1. Field of the Invention
The present invention relates to a method and device for preparing a paste-like compound for sealing an insulating glass pane.
2. Description of the Prior Art
The invention is based on a device comprising the features specified in the preamble of claim 1. Such a state of the art is known from DE 35 42 767 A1 and from DE 39 29 608 A1, which disclose a device for delivering two highly viscous substances in the predetermined proportion from two storage containers to a nozzle, by means of which the edge joint of an insulating glass pane is sealed. The two highly viscous substances, which are the two components of a two-component sealing and adhesive compound, are in each case delivered by means of piston pumps from barrels into an intermediate storage unit, which is a piston-cylinder unit, from which a first piston presses the main component (binder or base component) of the sealing and adhesive compound and a second piston presses the additional component (hardener) synchronous to the main component. Main component and additional component are delivered on the delivery path between the piston-cylinder unit and the nozzle by means of a static mixer in which they are mixed with each other.
In the event that the supply of the main component and of the additional component in the piston-cylinder unit comes to an end, the sealing process of the insulating glass pane must be interrupted to refill the main component and the additional component into the respective piston-cylinder unit. During this time, a sealing of insulating glass panes is not possible. When attempting to avoid interruptions of the sealing process, the storage volume of the piston-cylinder unit must be chosen as large as possible. Due to the inevitable compressibility and due to a thixotropic behavior of the constituents of the sealing and adhesive compound, the accurate metering thereof to the extent that neither too much nor too little of the compound reaches into the edge joint of the insulating glass pane becomes more difficult, with an increasing size of the storage volume. The impact of the compressibility and the thixotropic characteristics of the paste-like compound is important in particular because pressures of from 200 bar to 250 bar must be applied for the delivery of the paste-like compound. The weight of the piston-cylinder units, the amount of force required for the actuation thereof, the pressure on the material, which is to be delivered, and thus also the weight for the drives of the pistons of the piston-cylinder units furthermore increase with an increasing storage volume.
To keep the delivery paths from the piston-cylinder units to the nozzles short, it is known to arrange the nozzle and the piston-cylinder units, which feed the nozzle, on a common carrier. This carrier must be movable, so as to be able to move the nozzle along the edge of the insulating glass pane. The effort for the motion drive also increases with the weight of the piston-cylinder units.